The first I.S. machine was patented in U.S. Pat. Nos. 1,843,159, dated Feb. 2, 1932, and 1,911,119, dated May 23, 1933. Today more than 4000 I.S. machines, manufactured by a number of companies, are in use worldwide, producing more than a billion bottles every day of the year. An I.S. (individual section) machine has a plurality of identical sections (a section frame in which and on which are mounted a number of section mechanisms) each of which has a blank station which receives one or more gobs of molten glass and forms them into parisons having a threaded opening at the bottom (the finish) and a blow station which receives the parisons and forms them into bottles standing upright with the finish at the top. An invert and neck ring holder mechanism which includes an opposed pair of arms, rotatable about an invert axis, carries the parisons from the blank station to the blow station inverting the parisons from a finish down to a finish up orientation in the process. A bottle formed at the blow station is removed from the section by a takeout mechanism.
Machine productivity has been increased by increasing the speed of the I.S. machine (the cycle time of a section), by increasing the number of gobs handled per section from one, to two, to three, and even to four, and by increasing the number of sections. These improvements were done without substantially increasing the width of a section. This was fundamental since the measure of productivity is viewed as the number of bottles produced per unit of time in a given width of machine, i.e., the effective productivity. This means that if an improvement increased the width of a six section machine to the width of a standard 10 section machine, with machine speed and section capacity being unchanged, the effective productivity would decrease 40%.
The blank station includes opposed pairs of blankmolds and the blow station includes opposed pairs of blowmolds. These molds are displaceable between open (separated) and closed positions. Opposed pairs of neck ring molds, carried (supported proximate their tops) by the invert and neck ring holder mechanism, define the finish of the bottle and hold a formed parison as it is transferred from the blank station to the blow station.
The blankmolds and the blowmolds in the '159 patent are supported on inserts carried by opposed carriers which are pivotal about a common pivot in front of the molds (front to back movement is defined by the movement of a parison from the blankmolds to the blowmolds). Both the blankmold support mechanism and the blowmold support mechanism are operated by a linear motor (a fluid operated motor). The linear motor for the blankmold support mechanism is mounted in front of the pivot for the blankmold support mechanism and extends horizontally outwardly from the front of the section frame and a pair of links connect the output of the blank side motor with the blankmold support mechanism. The linear motor for the blowmold support mechanism is mounted vertically at the side of the pivot (these mechanisms at either station are generally referred to as a mold opening and closing mechanism). That initial I.S. machine evolved to a machine where the motors (fluid operated cylinders or rotary output motors) are located below the molds and each motor is connected to the associated pair of mold carriers via transmissions which extended vertically from the bottom of the section at the front or back of the pair of mold support mechanism (see U.S. Pat. Nos. 4,362,544 and 4,427,431). The drive linkages exerted twisting forces through the carriers and this was undesirable. Additionally, the drive linkages must be designed for specific mold configurations and it is common for the entire linkage as well as the mold support mechanism to be changed when switching from one gob configuration to another. In such machines the baffle mechanism and the funnel mechanism, must be located at the side of the section proximate the middle, making the service of these mechanisms difficult, often requiring that adjacent sections be turned off. In such mold opening and closing mechanisms, nothing locks the molds at the desired mold closed position when the parison is made and as a result, the mold halves can be pushed apart imparting an enlarged vertical seam in the parison and hence the final bottle. To prevent this, linkages have been designed to prevent opening of the molds at the closed position (see U.S. Pat. No. 5,019,147).
A variation of the I.S. machine, disclosed in U.S. Pat. No. 4,070,174, is called the A.I.S. machine. In this machine, which is sold today, the pairs of mold support mechanisms are mounted for axial ("A") rather than pivotal motion and are operated by motors in a conventional manner. A machine which is a derivation of the I.S. machine, is the I.T.F. machine, which is disclosed in U.S. Pat. No. 4,443,241. This machine, which has three forming stations (blank, reheat, and blow, i.e., triple forming ("T.F.")), was not successful. In this machine the motor for the blank and blow mold carrier pairs was a vertically extending linear motor located immediately below the center of the molds. This machine also advanced the blank and blow mold halves axially.
Such mold open and close mechanisms are extremely complex, being defined by a very large number of parts, specially designed for a specific machine configuration, which occupy a large portion of the section frame or housing. This makes these mechanisms very expensive and often requires, in effect, a rebuilding of the machine by changing the entire mechanism to change the machine configuration. It additionally makes it very difficult to complete the required piping for the section mechanisms. Service air must be supplied in ducts located in front of, in back of, or on top of the section frame and this makes piping costs very expensive. Furthermore, an inherent problem with I.S. machines is that dimensional growth due to heat at the blank side occurs towards the axis of the invert and neck ring holder mechanism while dimensional growth due to heat at the blow side occurs away from the axis of the invert and neck ring holder mechanism. Finally, the force applied will not be transmitted directly to the inserts which support the molds since the carrier which supports the inserts is in the force path and as a result the inserts can be subjected to twisting forces when a clamping load is applied.